$\"\"$

Newtons law of cooling:

The rate of change in temperature of an object is proportional to difference between the object temperature $\"\"$ and surrounding medium temperature $\"\"$ .

Rate of change of temperature with respect to time is denoted as $\"\"$ .

Difference between the object temperature $\"\"$ and surrounding medium temperature ( $\"\"$ ) is $\"\"$ .

Definition of Newtons law of cooling:

$\"\"$

Hence $\"\"$

$\"\"$

Newtons law of cooling is $\"\"$ .